Donut farming is great fun!!
After several years of playing and earning money which there never seemed anything to spend on, I discovered that if I purchased multiple ‘rat trap delivery trucks’ my XP would go up at a faster rate. This coupled with the ‘Xp accelerator’ (x5 xp) my donut count went bonkers. I’m now on level 939 and have an excess of those delicious goodies. Hope this helps
Xx